THE perpetual struggle of new mothers to shed their "baby weight" is so well documented that the market is saturated with books, DVDs and experts proffering advice.

Little consideration on the matter has historically been given to the father, perhaps for obvious reasons.

However, research has found that men put on an average of one and a half stone after having a child.

A lack of time to exercise, increased consumption of takeaway meals and sleepless nights are said to be to blame as pressures mount on the “modern dad”.

The study found that 40 per cent of new fathers are unable to pull their weight in the family home because they are so exhausted.

One in ten has to “gear himself up” to rejoin hectic family life at the end of the working day and one quarter admit having to sneak in naps during week days in order to cope. A fifth have fallen asleep whilst reading to their children.

Paul Keenan of Benenden Healthcare, which carried out the study in conjunction with the Men's Health Forum, said the modern lifestyle was having an impact on fatherhood.

"As we approach Father's Day, we discover that the modern dad's health is suffering under the strain from diverging pressures such as work and family life,” he said.

"As a result, dads are taking shortcuts with their diets, leading to increased weight, more sedentary lifestyle and eventually running the risk of health scares.”

One in three of the 2,000 fathers questioned said that financial pressures and fears about job stability also played a part.

Researchers warned that the family unit was suffering as a result, with many fathers claiming that they felt too fed up or too tired to play with their children and admitting that they snapped at them as a result of being over worked and under nourished.

Adrienne Burgess, joint CEO of the Fatherhood Institute, highlighted previous research which found that men put on an average of seven pounds when their partner was pregnant.

“It is largely due to lifestyle as they stay in more,” she said. “But when a child is born most men, just like the mothers, are running around from morning until night and become far more home-focused.

“It is really up to both parents to make time for the other to get out and go for a jog or go to the gym. Twenty minutes exercise three times a week acts like a mild anti depressant, it’s very important.”

But while the strain of having a new baby is blamed for the initial weight gain, research suggests that the extra pounds are rarely shed.

Sixty per cent of young adults aged between 18 and 30 said their father was not fit or healthy while half said he was overweight.

Although 46 per cent said their father regularly made a joke about having a large stomach, a third considered him stubborn and said he would refuse to deal with health issues unless pushed.

Dr Ian Banks, president of the Men's Health Forum said: "Men are facing an uphill struggle with their health when they become fathers.

"The survey shows even their kids know it. Heart disease is the biggest cause of premature death in men.

"We're saying you only live once, if you want to be around to see your kids grow up you need to stay healthy."